Adjustment element for an overrun air recirculation valve

ABSTRACT

An adjustment element for a divert-air valve. The adjustment element includes an actuation element which moves translatorily, and a control body which moves with the actuation element. The control body includes a first hollow body and a second hollow body. The first hollow body includes an outer surface which is circumferentially closed so as to define an interior, a first axial end, and an annular plate which extends radially inward from the first axial end. The second hollow body includes a radially outer annular plate which is sealingly fastened in an encircling manner axially to the annular plate of the first hollow body, and a radially inner region in which an outer surface extends in a direction of the actuation element in the interior of the first hollow body.

The invention relates to an adjustment element for a divert-air valve, comprising an actuation element which is movable in a translatory manner and a control body which is movable with the actuation element.

Divert-air valves for recirculation of condensed fresh gas, optionally with recirculated exhaust gas, from the pressure side of a compressor of a turbocharger back to the suction side of the compressor, are widely known. The connection between the pressure side and the suction side of the compressor via a bypass line is required for the transition from a high load into the coasting operation of the internal combustion engine so as to prevent a high conveyance of the booster pump against a closed throttle flap and the resultant pumping effect, and to prevent a too strong sudden drop of the turbo speed with the result of thermodynamic problems.

Divert-air valves are frequently operated electromagnetically, wherein the valve closure body of the valve is moved via the armature by the electromagnetic force. An example of such an arrangement is described in DE 100 20 041 A1. Control is performed via a control unit in accordance with correspondingly existing motor data. The valve comprises a pressure compensation opening on the valve closure body whereby, with a corresponding design of the effective surfaces, a balance of forces is established for the pneumatic forces. In this valve, the closure body is connected directly to the armature, and the interior of the valve is separated from the outer region via a membrane. In the armature and the closure body, a bore is formed via which a pressure compensation is established between the pressure side of the turbo charger and the interior of the valve.

In the subsequent generations of divert-air valves, a valve is normally omitted so that there is used a substantially cylindrical control body which is connected in a gimbaled manner to the armature and which in the radially outer region is sealed by a sealing ring instead a membrane. Such a divert-air valve is known e.g., from DE 10 2010 026 121 A1. The substantially cylindrical control body comprises, at its end facing toward the armature, a constriction which has a widened portion of a sliding sleeve gripping behind it which is connected to the armature so that the armature together with the sliding sleeve and the control body will be lifted off the valve seat or be lowered onto the latter.

In other publications, such as WO 2014/102133 A1 or DE 10 2004 044 439 B4, there is provided, directly at the armature, a constriction followed by a widened portion so that the control body, after having been inserted via the widened portion, will grip into the constriction and thus be fastened in a form-locking manner. For this purpose, the control body has to be provided with radially inward facing, resilient elements. In correspondence thereto, the control body is normally produced as a plastic part which, however, is of limited thermal resistance.

The ends of these control bodies facing toward the valve seat consist of the axial ends of their cylindrical outer surface. In correspondence thereto, these arrangements have the disadvantage that, for turbo chargers generating different pressures, it will be required in each case to design new shapes for the control bodies, wherein the diameters of these shapes must be adapted to the cross sections that are to be sealed. Further, due to the plastic material that is to be used, these arrangements are often not suited for the increasing operating temperatures. Further, problems occur by too noisy closing and opening movements. Primarily, problems may occur with respect to the sealing tightness.

Thus, there is posed the object to provide an adjustment element for a divert-air valve that will open and close with merely minimum noise, is inexpensive in production, is thermally resistant and has high leak tightness. Further, it is desired to reduce production costs by allowing for adaptation to different cross sections that are to be sealed.

The above object is achieved by an adjustment element comprising the features defined in the main claim 1.

Since the control body comprises a first hollow body having a circumferentially closed outer surface from the first axial end of which an annular plate extends radially inward, and a second hollow body having a radially outer annular plate which is sealingly fastened in encircling manner axially to the annular plate of the first hollow body and from the radially inner region of which an outer surface extends in the direction of the actuation element in the interior of the first hollow body, it is achieved that the control body can be adapted with respect to its shut-off cross section in a simple manner. By the simple shape of the individual component parts, the adjustment element can be produced in a simple and cost-effective manner, and it will be possible to choose thermally resistant materials such as e.g., sheet metal. Sealing tightness between the components can be safeguarded as well.

Preferably, the outer surface of the first hollow body is cylindrical. Such a shape can be produced in a particularly simple manner, and sealing tightness on the outer circumference will be safeguarded through the entire stroke range.

According to a modification of the above embodiment, the outer surface of the first hollow body is designed with a conically widening shape in the direction toward the actuation element. In this manner, tight closure is safeguarded in the closed state of the valve while, during stroke movement, wear of the surrounding sealing is minimized.

Advantageously, in the outer surface of the second hollow body, at least one opening is formed via which the pressure compensation between the bottom side of the adjustment element and the interior of the valve can be established in a simple manner.

According to a preferred embodiment, the control body is fixedly connected to the actuation element. This can be realized either directly or via intermediate components. In each case, there is safeguarded a direct movement coupling between the actuation element, normally designed as an armature, and the control body.

Preferably, the actuation element has a connection element fastened to it which extends into the interior of the second hollow body and which, on its end facing away from the actuation element, comprises a radially widened portion, and the second hollow body comprises a corresponding radial constriction arranged axially between the actuation element and said radially widened portion of the connection element, wherein the outer circumference of said radially widened portion of the connection element is larger than the inner circumference of the radial constriction of the second hollow body. Thereby, fastening the control body on the actuation element is realized in a simple manner, said fastening allowing for tilting movement of the control body relative to the actuation element without the need for deformation of any one of the components during the fastening process.

According to a modification of the above embodiment, as provided by the invention, the connection element is fastened in a central recess on the actuation element, the diameter of said central recess corresponding to the outer diameter of the connection element in the region extending into the recess. In this manner, the connection element at the same time serves for centering the control body relative to the actuation element. This will facilitate the assembly process of the adjustment element.

Preferably, an elastomer is arranged between the connection element and the second hollow body, thus allowing for a dampened movement between the connection element and the control body. This makes it possible to allow for an easy tilting of the control body and, further, to achieve a dampening of noise during the movement.

According to a modification of the above embodiment, the elastomer extends from the actuation element up to the radially widened portion of the connection element and fills a space that is located axially between the radially widened portion and the radial constriction of the second hollow body. Correspondingly, the elastomer has a damping effect both in axial direction and in radial direction and, if desired, can seal the space between the fastening element and the second hollow body. Further, the elastomer can be designed to comprise axial connections which are completely or partially distributed along the circumference in a uniform or non-uniform manner, said connections effecting a pressure compensation between the interior and the pressure chamber before the closure body.

For generating the pressure-balanced state of the adjustment element in the valve, the second hollow body is formed with a plurality of openings, distributed along the circumference, in a region between the radial constriction of the second hollow body and the annular plate of the second hollow body. These openings can be generated in a simple manner e.g., by punching, and they present a sufficient through-flow cross section for fast pressure compensation in case of rapidly changing pressures.

Advantageously, on the side of the annular plate of the second hollow body remote from the actuation element, a sealing ring is fastened whose diameter corresponds to the largest diameter of the first hollow body. On the one hand, this will effect a leak-tight closure upon placement on the valve seat and, further, this will lead to identical force application surfaces on the axially opposite sides of the adjustment element so that a balance of forces is generated which will require merely small adjustment forces and thus will guarantee extremely short actuation times.

Preferably, radially between the two hollow bodies, a spring is arranged which bears in an axially biased state onto the radially inward extending plate of the first hollow body. Thereby, return movement of the adjustment element to its position for closing the duct will be safeguarded. In this arrangement, the spring can be installed in a particularly simple manner.

According to a preferred embodiment of the invention, the two hollow bodies and the connection element are produced as deep-drawn parts from sheet metal. Correspondingly, the closure element can be produced in a very cost-effective manner while at the same time offering high strength, corrosion resistance and thermal resistance.

Preferably, the two hollow bodies are fastened to each other and/or the connection element is fastened to the actuation element by welding, bonding, flanging or crimping. Also these connecting techniques can be practiced in a cost-effective manner and guarantee a long lifespan of the connection.

Thus, there is provided an adjustment element for a divert-air valve that will safeguard high durability and leak-tightness and can be produced in a cost-effective manner. Further, adaptation to other cross sections is possible in a simple manner without the need to change shapes. This closure element can be switched with a low noise level and is thermally resistant.

An embodiment of a divert-air valve comprising a closure element according to the invention is illustrated in the Figures and will be described hereunder.

FIG. 1 shows a sectional lateral view of a divert-air valve comprising an adjustment element according to the invention.

FIG. 2 shows a sectional lateral view of the adjustment element according to the invention.

The divert-air valve shown in FIG. 1 comprises an electromagnetic actuator 10 in whose housing 12 a coil 14 is arranged on a coil carrier 16. In the radially inner region of coil carrier 16, there is fastened a magnetizable core 18 whose axial end extends beyond coil carrier 16, wherein, on this axial end, the core 18 is surrounded by a return plate 20 which is arranged in connection with a yoke 22 surrounding the coil. On the end of coil carrier 16 opposite core 18, a second further plate 24 is arranged which in the radially outer region is in contact with yoke 22 and which comprises an inner axial extension portion 26 extending into coil carrier 16. In the radial interior of this portion 26, a guide sleeve 28 is arranged which extends all the way until entering a central recess 30 of core 18 and in which an armature acting as an actuation element 32 is supported. The coil 14 can be supplied with power via conduits 34 entering a plug 36.

As soon as, in this manner, a sufficiently large current is flowing in core 14, a magnetic field is generated by which the actuation element will be adjusted in the direction of core 18.

Thus, actuation element 32 serves as a first component of an adjustment element 38 which additionally comprises a control body 40 fastened to actuation element 32, wherein, by means of said control body, a through-flow cross section between an inlet and an outlet of a flow housing, not shown, can be cleared or blocked by lowering or lifting the control body 40 onto and resp. off from a valve seat surrounding the through-flow cross section.

According to the invention, said control body 40 comprises a first hollow body 42 and a second hollow body 44 which is arranged in the radial interior of the first hollow body 42. The first hollow body 42 comprises a cylindrical outer surface 46 which is closed along its circumference, wherein, on the end of said outer surface facing away from actuation element 32, an annular plate 48 is formed that extends radially inward. On said plate 48, there is additionally formed an annular bulge 50 facing away from actuator 10. The opposite axial end 52 of the first hollow body 42 is entirely bent to the outside so as to avoid sharp edges on the side facing toward actuator 10. This hollow body 42 is produced by deep-drawing from sheet metal.

The second hollow body 44 is likewise produced by deep-drawing from sheet metal and comprises a radially outer annular plate 54 from whose inner periphery an outer surface 56 extends into the inner region of the first hollow body 42 of which the annular plate 48 is arranged axially between the actuator 10 and the annular plate 54 of the second hollow body and which by its bulge 50 rests on annular plate 54 and is circumferentially welded to the latter. The radially outer region of the annular plate 54 of the second hollow body has a sealing ring 58 molded to it whose effective diameter for abutment on the valve seat corresponds to the diameter of the cylindrical outer surface 46 of the first hollow body. The outer surface 56 of the second hollow body conically tapers in a first portion 60 that is axially followed by a cylindrical portion 62 in which ten radial bores are formed, serving as openings for pressure compensation. Said cylindrical portion 62 is followed by a radial constriction 66 from whose inner diameter a further cylindrical portion 68 extends in the direction of actuation element 32, which portion correspondingly has a smaller diameter than the first cylindrical portion 62. On its axial end, said cylindrical portion 68 is slightly curved inward.

The cylindrical portion 68 as well as the radially inner part of constriction 66 have an elastomer 70 molded around them which extends beyond the cylindrical portion 68 in the direction toward the actuation element and bears against actuation element 32.

To fasten the control body 40 to the actuation element, use is made of a connection element 72 which again is produced by deep-drawing. Said connection element 72 is substantially pot-shaped, wherein a bottom 74 is arranged in a central circular recess 76 at the axial end of actuation element 32 and, on this site, is fastened by welding. The cylindrical portion 78 following said bottom 74 extends on the second hollow body 44 up to the end of said elastomer 70 facing away from actuation element 32 and has an outer diameter that is smaller than the inner diameter of elastomer 70. This cylindrical portion 78 is followed, on the side opposite to said bottom, by a radially widened portion 80 which radially extends substantially up to the radially outward end of elastomer 70 and whose outer diameter is thus larger than the inner diameter of the constriction 66 of the second hollow body 44. A space 82 that is formed during assembly of the adjustment element 38 and extends axially between the constriction 66 of second hollow body 44 and the widened portion 80 of connection element 72, is correspondingly filled by the elastomer 70 which, when connection element 72 is welded to actuation element 32, will be slightly compressed.

In housing 12, a chamber 84 is formed into which the control body can be immersed upon actuation of the valve. Said chamber 84 is radially delimited by a housing wall 86 wherein, at the end of said housing wall facing away from actuator 10, a ring-shaped plate 88 is formed whose inner diameter is slightly larger than the outer diameter of the first hollow body 84. Supported on this plate is a V-shaped sealing 90 comprising two legs, wherein the first one of these legs bears against the circumferentially closed outer surface 46 of first hollow body 42 and the second leg bears against the radially limiting housing wall 86 so that, in the closed state of the valve, the chamber 84 is connected to the duct arranged thereunder exclusively via the openings 64. To supply a corresponding pressure also to the central recess 30 between actuation element 32 and core 18 and thus to provide a pressure-compensated valve, one or a plurality of grooves are formed on the outer circumference of actuation element 32. To further safeguard that, in a non-powered condition of coil 14, the control body 40 will be placed into its state resting on the valve seat, a helical spring 94 is arranged in the interior of the first hollow body 42, wherein said spring rests in a tensioned state against plate 48 of first hollow body 42 and, by its opposite axial end, bears against housing 12 of actuator 10.

Thus, upon movement of the adjustment element 38 according to the invention, the control body 40 is allowed to slightly tilt relative to the actuation element 32 so as to effect a safe closure. Nonetheless, all movements will continue to be damped by the elastomer 70 so that switching noises will be avoided. The control body can be connected to the actuation element in a simple and durable way. Further, it can be produced in an inexpensive manner by deep-drawing of sheet metal and is highly thermally resistant. The entire system is distinguished by high leak tightness, thus allowing for short opening and closing times.

It should be evident that the scope of protection of the present invention is not limited to the described exemplary embodiment. The adjustment element according to the invention is also suitable for other actuators so that the actuation element does not necessarily have to be an armature of an electromagnet. Further, such an adjustment element can also be used for controlling the through-flow cross section of other liquid- or gas-conveying ducts. Also the shape of the control body can be modified within the scope of protection of the main claim. 

1-14. (canceled)
 15. An adjustment element for a divert-air valve, the adjustment element comprising: an actuation element configured to move translatorily; and a control body configured to move with the actuation element, the control body comprising, a first hollow body comprising an outer surface which is circumferentially closed so as to define an interior, a first axial end, and an annular plate which is configured to extend radially inward from the first axial end, and a second hollow body comprising a radially outer annular plate which is configured to be sealingly fastened in an encircling manner axially to the annular plate of the first hollow body, and a radially inner region in which an outer surface extends in a direction of the actuation element in the interior of the first hollow body.
 16. The adjustment element as recited in claim 15, wherein the outer surface of the first hollow body is cylindrical.
 17. The adjustment element as recited in claim 15, wherein the outer surface of the first hollow body is configured to have a conically widening shape in a direction towards the actuation element.
 18. The adjustment element as recited in claim 15, wherein the outer surface of the second hollow body comprises at least one opening arranged therein.
 19. The adjustment element as recited in claim 15, wherein the control body is fixedly connected to the actuation element.
 20. The adjustment element as recited in claim 19, wherein, the actuation element comprises a connection element fastened thereto, the connection element being configured to extend into an interior of the second hollow body and comprising a radially widened portion on an end facing away from the actuation element, and the second hollow body further comprises a radial constriction arranged axially between the actuation element and the radially widened portion of the connection element, the radial constriction being configured to correspond with the radially widened portion, wherein, an outer circumference of the radially widened portion of the connection element is larger than an inner circumference of the radial constriction of the second hollow body.
 21. The adjustment element as recited in claim 20, wherein, the actuation element further comprises a central recess arranged therein, the connection element is extends into and is fastened to the central recess on the actuation element, and a diameter of the central recess corresponds to an outer diameter of the connection element in a region where the connection element extends into the central recess.
 22. The adjustment element as recited in claim 20, further comprising: an elastomer arranged between the connection element and the second hollow body.
 23. The adjustment element as recited in claim 22, wherein, the radial constriction of the second hollow body and the radially widened portion of the connection element are arranged so as to provide a space located axially therebetween, and the elastomer is configured to extend from the actuation element up to the radially widened portion of the connection element and to fill the space.
 24. The adjustment element as recited in claim 20, wherein the second hollow body further comprises a plurality of openings distributed along a circumference thereof and arranged in a region between the radial constriction and the annular plate.
 25. The adjustment element as recited in claim 20, wherein at least one of the first hollow body, the second hollow body, and the connection element are produced as a deep-drawn part from sheet metal.
 26. The adjustment element as recited in claim 20, wherein at least one of the first hollow body and the second hollow body are fastened to each other, and the connection element is fastened to the actuation element, via a welding, a bonding, a flanging or a crimping.
 27. The adjustment element as recited in claim 15, further comprising: a sealing ring fastened on a side of the annular plate of the second hollow body which is remote from the actuation element, the sealing ring comprising a diameter which corresponds to a largest diameter of the first hollow body.
 28. The adjustment element as recited in claim 15, further comprising: a spring arranged between the first hollow body and the second hollow body, the spring being configured so that, in an axially biased state, the spring bears onto the annular plate of the first hollow body. 